颗粒物面源模式计算方法

对颗粒物面源模式做了深入研究，确定了颗粒物粒子面源开始沉降的位置。颗粒物粒子在面源内部不考虑沉降问题，面源源块内颗粒物浓度等于单位面积污染物源强与地面反射系数之积除以地面风速。面源源块外面开始考虑粒子沉降，采用虚点源后置法，参考颗粒物点源的部分反射倾斜烟云模式，全面给出了面源的颗粒物模式。面源边缘浓度采用线性内插方法处理，以免计算结果不连续。面源中心点位置应该在水平x，y方向平移一个微小距离，以消除计算点和面源中心点重合的可能。     

焦炉煤气制甲醇的精馏工艺的选择与生产指标控制

本文阐述了甲醇精馏工艺选择中应注意的几点问题，对甲醇精馏中所出现的问题，包括酸碱度的控制、甲醇水混溶性控制和乙醇指标的控制等作了详细的分析，提出了相应的解决方案。     

多孔介质中混溶驱动问题的时空局部网格加密有限差分格式

给出了多孔介质中一维混溶驱动问题在时间和空间上进行局部网格加密的有限差分格式,压力方程采用中心差分格式近似,饱和度方程采用修正迎风格式,且在交界面上采用线性插值,并利用极大值原理给出了误差估计。最后给出了数值算例。     

多孔介质中两相完全可压缩可混溶驱动问题的修正迎风差分法

本文采用修正迎风差分方法处理多孔介质中两相完全可压缩可混溶驱动问题,建立了差分计算格式,并证明了格式的收敛性,同时得到l^2和h^1误差估计,最后数值试验证明了方法的有效性。     

距离平方反比定律的应用与探讨

距离平方反比定律是电离辐射计量中常用到的一个定律,即在点源的辐射场中,某点的剂量率与该点和源的距离的平方成反比关系。本文通过测量点源辐射场中两个不同距离上的剂量率,根据距离平方反比定律计算出测量点相对于点源的距离,进而确定γ射线空气比释动能标准装置校准基点1米的位置和剂量率。     

计算二维矩形声腔传递矩阵及传递函数的声源模型探讨

计算二维矩形声腔传递矩阵的点源模型已在实际工程中取得了广泛应用，但是点源模型本身的奇异性使得传递矩阵的计算不精确。首先全面分析了线声源和面声源模型的声压收敛情况，证明线源和面源可以用来计算传递矩阵。然后详细讨论了点源和面源模型计算传递函数的区别，得出结论：面源模型更适合用于二维模型计算传递矩阵，收敛更快，可以消除点源模型计算的奇异性；点源模型可以计算体积流量的传递函数，但是计算压力传递函数会引起较大误差，这时需要用到面源模型。     

聚醚砜-聚丙烯腈共混膜的研究

在聚醚砜(PES)与聚丙烯腈(RAN)共混膜的制备中，PES和RAN聚合物较难混溶，在PES-溶剂-PAN体系中加入增溶剂，改变聚合物在溶液中聚集态，使聚合物实现较理想混溶．采用DSC，XRD，XPS以及ESEM压对共混膜进行表征，结果表明PES与PAN混溶较好，共混膜表面和断面的微孔分布均匀．共混膜废水处理水质优良．     

不可压缩可混溶驱动问题迎风区域分裂差分方法

结合区域分裂思想,本文给出了一维不可压缩可混溶驱动问题两种非重叠区域分裂迎风差分格式。由于饱和度的计算规模远大于压力方程,因此饱和度方程采用了迎风区域分裂差分法,内边界处和各子区域分别对应显隐格式。在稳定性条件下,给出了 l2 模误差估计,最后给出数值算例验证了理论结果。     

分层流体中水平运动潜体产生的内波分析

从线性化的Euler方程和连续方程出发，采用线性自由面条件，通过傅里叶变换法研究水平运动点源在分层流体中产生的内波．利用源汇分布法分析运动潜体产生的lee渡，采用稳定相法计算远场速度．计算结果表明，高模态内渡的渡域角小于低模态内波的渡域角，内渡的渡域角小于Kelvin波的渡域角；随航速增大lee波主要表现为散波．     

基于源汇分布法的浸水结构振动特性分析

提出了一个考虑线性波自由液面对浸水结构附连水质量影响的修正方法。基于源汇分布法应用伽辽金法获得线性波自由液面边界条件下虚拟点源位置及流体速度势的近似解,进而得到相应的附连水质量。以部分浸没悬臂板及某舰机舱双层底模型为研究对象,通过MATLAB程序计算它们的前三阶横向振动频率,计算结果分别与实验结果和有限元结果进行比较分析。结果表明该方法不仅可以较为准确地反应线性波自由液面对附连水质量的影响,尤其在结构浅吃水或低频振动的情况下修正效果更为明显,而且避免了求解大型动力学方程,提高了计算效率。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.